This invention relates to a fingernail and toenail shaping apparatus and more particularly to an improved abrasive belt cartridge that is removably attachable to a manicuring machine.
A fingernail and toenail shaping apparatus having a detachable and disposable belt cartridge is disclosed in U.S. Pat. No. 5,643,062, issued to the inventor James R. Joseph, the entire contents of which are hereby incorporated herein by reference. The cartridges can be easily replaced to facilitate course grinding, fine grinding, buffing, etc. Further, the use of easily interchangeable cartridges facilitates and promotes replacement of the cartridge whenever the machine is being used to file or buff fingernails and toenails of a different person, whereby better hygiene is achieved.
The cartridge is easily attached to and removed from a gear reduction module. In one embodiment, the belt cartridge is provided with a drive roller and an aperture through which a drive shaft extends into a keyed opening or socket of the drive roller to provide engagement between a drive shaft attached to the gear reduction module and the drive roller contained in the cartridge. Idler rollers and a tensioner having integrally formed spring portions with arcuate bearing surfaces at opposite ends of the tensioner define a circuitous belt path. The abrasive surface of the belt is available for fingernail and toenail shaping through an opening in the cartridge that extends generally between the idler rollers. Attachment of this embodiment of the cartridge to the gear reduction module is relatively easy. Attachment is achieved by aligning pins on the gear reduction module with slots on the back of the cartridge, inserting the pins into the slots, sliding the cartridge downwardly relative to the gear reduction module, and sliding a locking pin on the gear reduction module into engagement with the cartridge. However, a disadvantage of this embodiment, as disclosed in the patent, is that the provision of a drive roller in the cartridge increases the cost of manufacturing the cartridge. The idler rollers may be manufactured relatively inexpensively from thermoplastic materials. However, in order to achieve adequate frictional engagement between the drive roller and the inner surface of the abrasive belt and suitable mechanical coupling between a drive shaft and the drive roller, the drive roller generally comprises a metal hub onto which is mounted an elastomeric wheel or roller. Accordingly, the drive roller is relatively expensive to manufacture, such that it is more desirable to provide the drive roller on the manicuring machine, rather than in the cartridge.
In an alternative, more preferred, embodiment, a drive roller is secured to the drive shaft of the manicure machine, eliminating the need for a drive roller in the cartridge, thereby reducing the cost of the cartridge. In this embodiment, the cartridge is provided with an opening through which the drive roller attached to the manicuring machine extends into the belt cartridge to engage in inner surface of an abrasive belt contained within the cartridge. Although elimination of the drive roller from the cartridge provides a considerable cost savings, the abrasive belt of this embodiment can slip out of proper position after it is manufactured and/or after it is detached from the manicuring machine. When this occurs, the belt can obstruct the opening for the drive roller. To prevent damage to the abrasive belt and to achieve proper engagement between the abrasive belt and the drive roller, it is often necessary to carefully reposition the abrasive belt within the cartridge before and/or during attachment of the cartridge to the manicuring machine. This can be a cumbersome task that creates a perception of inconvenience, which could adversely affect market appeal for the product.
It would be desirable to provide a belt cartridge which is easily attachable to a manicuring machine, and which does not contain a drive roller. In other words, there is a need for a disposable belt cartridge for a fingernail and toenail apparatus that achieves the easy attachability of a belt cartridge containing a drive roller, while eliminating the drive roller from the belt cartridge to achieve a cost advantage.
A cartridge of U.S. Pat. No. 5,643,062 is attached to the gear reduction module of the manicure machine by aligning pins on the gear reduction module with keyhole-shaped slots in the back wall of the cartridge, pushing the pins into circular portions of the slots, sliding the cartridge relative to the gear reduction module, and then sliding a locking pin on the gear reduction unit toward the cartridge to engage a notch in the cartridge, whereby the cartridge is locked into proper position to prevent the cartridge from moving with respect to the gear reduction module and maintain the appropriate tension on the abrasive belt.
It would be desirable to simplify attachment of the cartridge to the manicuring machine. More specifically, there is a need for a belt cartridge which may be easily and securely attached to a manicuring machine without having to manipulate the abrasive bell during attachment of the cartridge to the machine, and which can be maintained in an appropriate locked position without performing a separate step of sliding a locking pin into the cartridge.
In accordance with a first aspect of the invention, a belt cartridge that is releasably attachable to a manicuring machine having a drive roller that is insertable into the belt cartridge for engagement of the drive roller with a flexible belt contained in the cartridge includes a retainer for holding the flexible belt in close proximity to a predefined circuitous path when the cartridge is not installed on the manicuring machine. The cartridge is defined by a easing having a front wall and a back wall. A flexible belt is disposed in the casing. The flexible belt has an abrasive outer surface for shaping fingernails and toenails and an inner surface for engaging a drive roller. The belt cartridge includes a first idler roller or bearing surface mounted in the casing for guiding the flexible belt around the circuitous path, and a second idler roller or bearing surface mounted in the casing for guiding the flexible belt around the circuitous path. When the cartridge is mounted onto the manicuring machine, the circuitous path is generally defined by the drive roller on the manicuring machine, and by the first and second idler rollers or bearing surfaces. An opening through the back wall of the casing allows insertion of the drive roller into engagement with the inner surface of the flexible belt. A first arcuate ridge projects from an inner surface of the front wall of the casing, and an opposing second arcuate ridge projects from an interior surface of the back wall of the casing. The opposing first and second arcuate ridges together define a retainer for holding the flexible belt in close proximity to the predetermined circuitous path when a drive roller is not inserted into the casing, i.e., when the cartridge is not attached to the manicuring machine. The retainer eliminates any need for manipulating the flexible belt before or during attachment of the cartridge to the manicuring machine or after removal of the cartridge from the manicuring machine.
In accordance with another aspect of the invention, a belt cartridge that is releasably attachable to a manicuring machine having a drive roller that is insertable into the belt cartridge for engagement of the drive roller with a flexible belt contained in the cartridge is configured to be securely mounted on the manicuring machine without the need for a locking pin. The belt cartridge includes a casing having a front wall and a back wall. A flexible belt is contained in the casing. The flexible belt includes an abrasive outer surface for shaping fingernails and toenails and an inner surface for engaging a drive roller. A first idler roller or bearing surface is mounted in the casing for guiding the flexible belt around a predefined circuitous path, and a second idler roller or bearing surface is mounted in the casing for guiding the flexible belt around the circuitous path. An opening through the back wall of the casing is provided to allow insertion of a drive roller into engagement with the inner surface of the flexible belt. At least one fastener slot through the back wall of the casing is provided for engagement with a fastener projecting from a cartridge mounting face on the manicuring machine. A protuberance on the back wall of the cartridge is provided for engagement with a recess in the mounting face of the manicuring machine to inhibit movement of the cartridge with respect to the manicuring machine. This engagement between the protuberance on the cartridge and the recess on the manicuring machine locks the cartridge onto the manicuring machine during normal use without the need for a separately actuated locking pin.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.